Containers in particular, can contain a fluid bottled in a sterile manner. The fluid can be removed from the container by a cannula, for example a syringe needle or a mandrel, as widely used, particularly for medical applications, for example in the form of ampules or infusion bottles. In the case of medical applications, such containers, which are made out of plastic using the blow-fill-seal method or the known Bottelpack® method, are especially suitable because the product is only in contact with a polymer. These containers therefore offer a high degree of protection against microbial contamination, even during long periods of storage under unfavorable environmental conditions. Plastic products of this kind have been disclosed, for example, in U.S. Pat. No. 5,897,008 A or EP 2 269 558 A1. When the product is to be removed by an insertable cannula or an insertable mandrel, such containers are only suitable for a single use, since resealing the containers is not possible after an initial opening thereof, because the polyolefins used in such BFS containers are not nearly elastic enough to reliably seal the puncture site. To remedy this problem, insertion parts or stoppers made out of rubber are known to be used in BFS containers that are intended for medical purposes. As a result, on the one hand, the manufacturing process is made substantially more costly and is slowed by this insertion. In addition, sterilizing the rubber parts is necessary before inserting them to maintain low bacterial levels in the product. A serious disadvantage is the fact that the product is in contact with the insertion part, even during the storage period. U.S. Pat. No. 5,467,878 A, EP 0 721 897 A1, DE 2 844 206 C2 and DE 2 327 553 A1 disclose containers having caps, which have a rubber insert. The caps are pressed onto the container head and are fixedly connected to the neck of the bottle by a mechanical fixation. Since the rubber insert is pressed onto the flexible, thin container wall only by mechanical structure, a gap always remains as a result of the design. Unwanted microbiological contamination, bacterial growth, fungus, etc. may easily arise in this gap or space. This contamination can easily find its way into the container when the container head is pierced. In addition, fluid can be easily drawn in a suction process as a result of capillary action, and thus, may find its way into the space between the insert and the container head.
To avoid the problems associated with rubber inserts, a container of the above mentioned generic type is already known from EPO 364 783 A 1, in which, rather than a rubber material, a sealing material made out of a thermoplastic elastomer (TPE) is fixedly applied to a cap. That sealing material can be applied to the container head in such a way that the sealing material of the cap fits snuggly along the wall region of the container and is provided as a puncture site. A cavity or gap then cannot be avoided reliably between the container head and the sealing material, and fluid may possibly be drawn in a suction process as a result of a capillary action created by a thin gap. To ensure the sterility of the contact surface of the container head and sealing material, an autoclave process is also necessary, to which the contents of the container are also subjected. As a result, such container systems are only suitable for thermally stable products that can withstand the high temperatures (ca. 115° C. to 132° C.) of an autoclave process.